Does Whirlwind trigger deflect, and if so, who pays the deflect cost?

Ruling: Whirlwind does not trigger deflect because it does not target. Deflect is a passive ability that levies an additional cost only for spells or abilities that target the permanent with deflect.

Nuances:

• Deflect is not a trigger; it's a passive ability that adds a cost requirement
• The devs are aware that Whirlwind's interaction isn't fully accounted for in the CRD
• Based on both RAW (rules as written) and RAI (rules as intended), Whirlwind wouldn't require deflect to be paid